POEMs

Excessive Lowering of Blood Pressure May Cause Harm

Clinical Question: Can aggressive lowering of blood pressure in patients with coronary artery disease be dangerous?

Setting: Outpatient (any)

Study Design: Cohort (prospective)

Synopsis: Research has hinted at a J-curve response to lowering blood pressure: As blood pressure is lowered, mortality and morbidity decrease to a point after which further lowering is associated with higher mortality and morbidity. Common guidelines and conventional wisdom do not take this risk into account, advocating various degrees of aggressive blood pressure control on the basis of other risk factors. This is an analysis of the results of a study comparing the effectiveness of verapamil (Calan) and trandolapril (Mavik) in hypertensive patients with coronary artery disease.

In this analysis of 22,576 patients, the investigators evaluated the relationship between average diastolic blood pressure and the primary outcome of all-cause death, nonfatal stroke, and nonfatal myocardial infarction. The patients in this study were treated and monitored for a median of 2.7 years, and mortality and morbidity rates were not different between the two treatments. Blood pressure was divided into 10-mm Hg increments and was measured at each level of control. As in other research, the J-curve present in these data is associated with decreases in diastolic blood pressure.

The best results were a diastolic blood pressure between 80 and 90 mm Hg. A diastolic blood pressure between 70 and 80 mm Hg was associated with slightly, but not significantly, increased poor outcomes, although patients with blood pressures of less than 70 mm Hg experienced poor outcomes at the same rate as those with readings higher than 100 mm Hg.